Purity Of Chitin Research Articles

Microwave-assisted deep eutectic solvent extraction of chitin from crayfish shell wastes for 3D printable inks

Chitin, as one of the most abundant biopolymers in the world, has promising applications in various fields. However, critical challenges still remain in the extraction and value-added utilization of chitin in a cost-effective and environmentally-friendly manner. Herein, a time-saving, energy-efficient, and sustainable strategy consisting of microwave heating and deep eutectic solvents (DESs) treatment is demonstrated to extract the chitin from the crayfish shells. Benefitted from the release of hydrogen ion from acidic hydrogen bond donor of DESs and the formation of hydrogen bonding between DES components and protein, the minerals and protein are successfully removed using the choline chloride/lactic acid (CL) DESs. With the optimized extraction conditions, the high yield and purity of chitin is simultaneously obtained as 19.11% and 97.44%, respectively. Furthermore, the DESs can be recycled and reused for 4 times with ease, which is conductive to reducing the extraction cost and realizing the sustainable development. Finally, the extracted chitin can be further dissolved in DESs to prepare a viscoelastic ink, which displays superior rheological properties and 3D printability. This study provides a green and facile method for chitin production and opens an exciting avenue for the high value-added utilization of chitin as 3D printing ink.

Efficient extraction of chitin from crustacean waste via a novel ternary natural deep eutectic solvents

Extraction of chitin from crustacean waste with acidic natural deep eutectic solvents (NADESs) is usually accompanied by degradation of chitin, which lowers the yield and molecular weight of product. Herein, this study proposed a eco-friendly and feasible route for effectively improving the yield and molecular weight of chitin by introducing N-acetyl-D-glucosamine into ternary NADESs. A high molecular weight chitin with molecular weight of 3.92 × 105 Da, purity of 90.2% and yield of 85.6% was obtained from crab shell. Compared with conventional acid/alkali and binary NADESs method, the maximum yield of chitin extracted by ChCl-G-FA2 was increased by 1.57 times and 1.39 times respectively. Molecular weight of chitin was 3.16 times that of acid/alkali method. Recycling performance evaluation revealed that the purity of chitin could still reach 80.4% after five cycles of NADESs. This study provided a eco-friendly utilization strategy for crustacean waste based on multifunctional NADESs.

Sustainable Superheated Water Hydrolysis of Black Soldier Fly Exuviae for Chitin Extraction and Use of the Obtained Chitosan in the Textile Field.

Interest in insects as waste biomass bioconverters and their use as valuable resources for fat, proteins, and chitin has increased considerably in the last few years. In this study, proteins were extracted from defatted black soldier fly (BSF) (Hermetia illucens) exuviae by green hydrolysis using superheated water at 150 °C for 20 h, and the remaining chitin was deacetylated into chitosan and used as a finishing agent for polyester fabrics. A total amount of 7% fat, 40% proteins, and 20% chitin was obtained from BSF exuviae. Different hydrolysis times ranging from 1 to 20 h were tried until the complete purification of chitin. The purity of chitin and the obtained chitosan after deacetylation was assessed by Fourier transform infrared spectroscopy and thermal analysis. A preliminary study was successfully carried out to use the obtained chitosan as a finishing agent for polyester pretreated fabrics using citric acid as a grafting agent. The presence of chitosan on the fabric was verified by scanning electron microscopy and by dyeing of the pretreated polyester fabric using a reactive dye with sulfonated groups that are able to be absorbed by electrostatic attraction because of the created cationic nature of the fiber surface treated by chitosan.

Production of chitin and chitosan from shrimp shell wastes

A method was developed for commercial scale production of chitin and chitosan in Bangladesh from marine shrimp, P. monodon and freshwater prawn, M. rosenbergii shell and appendages. Chitin is a macro-molecular linear polymer of anhydro N-acetyl glucosamine (N-Acetyl, 2-Amino 2-Deoxy DGlucose) and chitosan is deacetylated chitin. For production of chitin, fresh shells of P. monodon having initial bacterial load of >105 CFU/g sample and peroxide values of >10 mmol free iodine liberated /kg of oil were washed with dilute sulfuric acid. Adhered proteins were removed by washing with low strength alkaline solution and then rinsed with water. Crude chitin thus prepared was treated with concentrated hydrochloric acid and purified chitin was obtained after treating with low strength alkali solution. Water soluble chitosan was prepared by performing a deacetylation process using 50% NaOH (w/w) at 100oC for 4-5 hours and then washed, dried and ground. For purification of chitin and chitosan, a series of experiments were conducted to optimize the level of NaOH concentration and time and temperature schedule of demineralization and deproteinization/deacetylation. A high temperature-short time schedule obtained best quality chitin and chitosan. Both subjective and objective methods were used for the testing of quality and purity of chitin and chitosan. Comparative studies between the quality of products from different components of the shell and from different shrimp/prawn species showed that both chitin and chitosan obtained from M. rosenbergii shell were better compared to those of P. monodon in terms of extractability, deacetylation, and color. Shells obtained better product compared to shrimp appendages. The study suggests that chitin and chitosan can be produced in existing shrimp/prawn processing plants of the country with the simple renovation.J. Bangladesh Agril. Univ. 14(2): 253-259, December 2016

Physicochemical comparison of chitin and chitosan obtained from larvae and adult Colorado potato beetle (Leptinotarsa decemlineata)

Chitins and chitosans obtained from larva and adult Colorado potato beetles (Leptinotarsa decemlineata) were physico-chemically characterized and differences between adults and larvae were identified. The dry weight chitin contents of the adult Colorado potato beetles and larvae were determined as 20% and 7%, respectively. The chitin produced chitosan yields of 72% from the adult Colorado potato beetles and 67% from the larvae. FTIR analysis showed that the isolated chitins were in the alpha form. Crystalline index values, determined by XRD, were 72% for larvae and 76% for adults. The degradation temperatures of the isolated chitin structures were measured by TGA, and this showed that the chitin from adult Colorado potato beetles had a more stable structure than that from the larvae. The surface morphologies of the isolated chitin and chitosan structures were analysed with SEM and it was revealed that these structures consisted of nanofibres. According to elemental analysis, the purity of chitin and chitosan from adults was greater than that from the larvae. The results of molecular analysis showed that the chitosans from adults (2.722kDa) and larvae (2.676kDa) of the Colorado potato beetle have low molecular weights. Antimicrobial and antioxidant activities of both adult and larval chitosans were determined. The adult potato beetle is more appropriate than the larvae as an alternative chitin source because of the fact that its dry weight chitin content, chitosan yield and purity of chitin are higher than those from the larvae, and its antimicrobial and antioxidant activities are also higher than those from the larvae.

The recovery of protein hydrolysate during enzymatic isolation of chitin from shrimp Crangon crangon processing discards

Shell waste from shrimp Crangon crangon processing is a good source of chitin and proteins, contained on a dry basis of the offals in amounts 17.8% and 40.6%, respectively. The digestion of the shells with proteolytic enzymes allow to recovery of the chitin and nutritionally valuable protein hydrolysate. These products were prepared from the shells preliminarily demineralized with 10% HCl solution at 20°C for 30 min using commercially available Alcalase at 55°C and pH 8.5. Recovered protein hydrolysate contained, on a dry basis, 64.3% of protein (N×6.25), 6.24% lipids and 23.4% of sodium chloride and had, at pH 4.0, a minimum solubility, and 81.7% of total nitrogen in the product. The PER value of the obtained product was 2.99 as compared with that for hydrolysates from capelin (2.64) and beef longissimus dorsi muscle proteins (2.81). The charcoal decolorization of the product decreased the PER and amino acid index (EAA) values from 2.99 and 125.4 up to 2.74 and 123.2, respectively. The total amount of residual small peptides and amino acids directly attached to chitin molecules and resistant to enzymatic hydrolysis depends on degree of hydrolysis (DH) and was about 4.4% at DH value of 30%. Such purity of chitin is sufficient for many purposes.